Battery module, manufacturing method thereof, and battery pack including the same

Abstract

To provide a battery module having excellent thermal insulation, fire resistance, and flame retardancy or non-flammability to inhibit propagation of heat in a cell to cells adjacent thereto due to thermal runaway of a battery, a method of manufacturing the same, and a battery pack including the same.SOLUTION: The present invention relates to a battery module. The battery module includes: a plurality of cells; an insulation sheet provided between the plurality of cells, the insulation sheet having an upper surface and a lower surface disposed so as to face cells adjacent thereto, respectively; and a foam layer formed on two or more surfaces including an upper portion surface, of a border side surface between the upper surface and the lower surface of the insulation sheet. The present invention further relates to a method of manufacturing the battery module, and a battery pack including the battery module.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a battery module, a manufacturing method thereof, and a battery pack including the same. [Background technology]

[0002] Secondary batteries are power storage systems that provide excellent energy density by converting electrical energy into chemical energy and storing it. Unlike primary batteries, which cannot be recharged, secondary batteries can be recharged, and are widely used in IT devices such as smartphones, cellular phones, laptops, and tablet PCs. In recent years, interest in electric vehicles has increased to prevent environmental pollution, and high-capacity secondary batteries are being adopted for electric vehicles. Such secondary batteries are required to have characteristics such as high density, high output, and stability.

[0003] On the other hand, when a battery contains a large number of high-capacity cells such as lithium-ion secondary batteries, there is a risk that one cell may overheat and experience thermal runaway, adversely affecting other adjacent cells, and therefore it is required that adjacent cells are thermally insulated from each other.

[0004] Therefore, conventionally, a plate material or an insulating resin plate is placed between the cells to insulate and heat the adjacent cells.

[0005] The above information disclosed in the Background of the Invention is intended to enhance the understanding of the background of the present invention only, and may therefore include information that does not constitute prior art. Summary of the Invention [Problem to be solved by the invention]

[0006] One embodiment provides a battery module having excellent heat insulation properties as well as fire resistance and flame retardancy or non-combustibility in order to suppress heat propagation between adjacent cells due to thermal runaway of a battery, a manufacturing method thereof, and a battery pack including the same. [Means for solving the problem]

[0007] One embodiment provides a battery module including a plurality of cells, insulation sheets provided between the plurality of cells and arranged such that their upper and lower surfaces face adjacent cells, respectively, and a foam layer formed on two or more surfaces, including an upper surface, of edge sides between the upper and lower surfaces of the insulation sheet.

[0008] The cell may be a secondary battery cell.

[0009] The heat insulating sheet may include a first substrate, a second substrate, and an aerogel layer disposed between the first substrate and the second substrate.

[0010] Each of the first substrate and the second substrate may be made of one or more materials selected from the group consisting of resins, metals, and inorganic materials other than metals.

[0011] The aerogel layer may include an aerogel, a fibrous support, and a functional material including a binder, a dispersant, or a combination thereof.

[0012] The aerogel has a BET specific surface area of ​​500 m 2 / g~1,000m 2 / g.

[0013] The fibrous support may be one or more fibers selected from the group consisting of natural fibers, silica fibers, glass fibers, ceramic fibers, carbon fibers, graphite fibers, mineral fibers, and polymer fibers.

[0014] The binder may include a water-based polymeric binder.

[0015] The dispersant may be one or more selected from the group consisting of a surfactant, a silane coupling agent, and a phosphate salt.

[0016] The aerogel layer may contain 10% by weight to 90% by weight of the aerogel, 5% by weight to 70% by weight of the fibrous support, and 0.5% by weight to 20% by weight of the functional material, based on the total amount of the aerogel layer.

[0017] The foam layer may include a foam material that foams when the ambient temperature rises to 100°C to 200°C.

[0018] The foam layer may contain one or more foaming agents selected from the group consisting of expanded graphite, organic foaming agents, and inorganic foaming agents.

[0019] The organic blowing agent may be one or more selected from the group consisting of azodicarbonamide, dinitropentamethylenetetramine, and oxybis(benzenesulfonylhydrazide), and the inorganic blowing agent may be one or more selected from the group consisting of hydrogen carbonates, carbonates, and organic acid salts.

[0020] The foam layer may have a thickness of 3% to 20% of the thickness of the heat insulating sheet.

[0021] The foamed layer may have a thickness after foaming that is 1000% to 3000% of the thickness before foaming.

[0022] The foam layer may be formed on both upper and lower opposing sides of the heat insulating sheet, or on the entire side surface.

[0023] The foam layer may have a thickness of 100% or more of the foam layer formed on the upper part of the side of the heat insulating sheet, the thickness of the foam layer formed on the lower part.

[0024] Another embodiment provides a method for manufacturing a battery module, the method including: arranging a plurality of cells; arranging an insulation sheet between the plurality of cells such that an upper surface and a lower surface of the insulation sheet face adjacent cells; and forming a foam layer on two or more surfaces, including an upper surface, of edge sides between the upper surface and the lower surface of the insulation sheet.

[0025] The step of forming the foam layer may occur before or after placing the insulation sheet between the plurality of cells.

[0026] Yet another embodiment provides a battery pack including the battery module. Effect of the Invention

[0027] A battery module according to an embodiment can suppress the propagation of heat and flames to adjacent cells due to thermal runaway of a cell.

[0028] In addition, the insulating sheet provided in the battery module according to an embodiment has excellent compression performance, mechanical strength, and dimensional stability in addition to thermal insulation properties, and therefore can prevent the aerogel layer from falling off due to external impact, making it easy to work with and preventing contamination of the mechanism. [Brief description of the drawings]

[0029] [Figure 1] FIG. 1 is a schematic diagram showing a structure of a battery module according to an embodiment. [Diagram 2] 4 is a schematic diagram illustrating a state after a foam layer is foamed in a battery module according to an embodiment. FIG. [Diagram 3] 1 is a schematic diagram showing a cross-sectional structure of a heat insulating sheet according to one embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0030] Although the present invention will be described in detail below so as to be easily understood by those skilled in the art, the present invention may be embodied in various different forms and should not be construed as being limited to the embodiments set forth herein.

[0031] According to one embodiment, a battery module includes a plurality of cells, insulating sheets provided between the plurality of cells and arranged such that their upper and lower surfaces face adjacent cells, respectively, and a foam layer formed on two or more surfaces, including an upper surface, of edge sides between the upper and lower surfaces of the insulating sheet.

[0032] The battery module having the above structure has excellent heat insulation properties, as well as fire resistance and flame retardancy or non-combustibility, and can suppress the propagation of heat and flame to adjacent cells due to thermal runaway of a cell. In addition, the heat insulation sheet has excellent compression performance, can ensure mechanical strength and dimensional stability, can prevent the aerogel layer from falling off due to external impact, and can facilitate work and prevent contamination of the mechanism.

[0033] In one embodiment, the cell may be a secondary battery cell. The secondary battery may be, for example, a lithium secondary battery. The lithium secondary battery may be manufactured in various forms, such as a lithium ion battery, an all-solid-state battery, or a lithium metal battery. For example, the lithium secondary battery may have a structure in which a positive electrode plate and a negative electrode plate, on which a positive electrode active material and a negative electrode active material are respectively applied, are arranged with a separator sandwiched therebetween, and are sealed in a battery case together with an electrolyte to form a secondary battery cell. Depending on the shape of the battery case to be formed, it may be classified into a cylindrical type, a rectangular type, or a pouch type, and a plurality of secondary battery cells are connected in series or parallel to form a battery module.

[0034] Such secondary batteries require high stability. For example, if the secondary batteries are overcharged, decomposition reactions of the positive electrode active material or electrolyte and other side reactions may occur, and these reactions may release heat, which may eventually lead to an explosion of the secondary battery cell.

[0035] In this regard, in the present invention, by placing an insulating sheet between each of the cells and providing a foam layer on the side of the insulating sheet, in addition to excellent insulation properties, the cell has fire resistance and flame retardancy or non-combustibility, and can suppress the spread of heat and flame to adjacent cells due to thermal runaway of a cell.

[0036] FIG. 1 is a schematic diagram showing a battery module having heat insulating sheets disposed between a plurality of cells and foam layers formed on the sides of the heat insulating sheets.

[0037] Referring to FIG. 1, a battery module 100 according to an embodiment may include a plurality of cells 10 and may include a heat insulating sheet 20 provided between each of the plurality of cells 10. Here, the heat insulating sheet 20 may be disposed such that an upper surface and a lower surface face the adjacent cell 10, respectively. Also, the heat insulating sheet 20 may include a foam layer 30 formed on two or more surfaces, including an upper surface, among the side surfaces. As a result, a battery module with improved safety can be provided by first blocking a flame during thermal runaway of one cell and minimizing the spread of the flame to other cells, and further, a secondary battery pack including the secondary battery module can be provided.

[0038] FIG. 2 is a schematic diagram showing a case where a foam layer foams and spreads at a certain temperature or higher.

[0039] Referring to FIG. 2, a battery module 100 according to one embodiment includes a plurality of cells 10 and insulating sheets 20 provided between the plurality of cells 10, and a foam layer 30 is formed on the side of the insulating sheet 20. When the ambient temperature rises above a certain temperature due to thermal runaway, the foam layer 30 expands to fill empty spaces within the battery module 100, thereby preventing flame propagation.

[0040] In one embodiment, the heat insulating sheet may include a first substrate, a second substrate, and an aerogel layer disposed between the first substrate and the second substrate, wherein the first substrate and the second substrate may form upper and lower surfaces of the heat insulating sheet, respectively, and may be disposed to face adjacent cells.

[0041] FIG. 3 is a schematic diagram showing the structure of a heat insulating sheet according to one embodiment.

[0042] 3, the heat insulating sheet 20 may be formed to have a structure including a first substrate 21, a second substrate 22, and an aerogel layer 23 provided between the first substrate 21 and the second substrate 22. Here, the first substrate 21 and the second substrate 22 may form the upper and lower surfaces of the heat insulating sheet 20, respectively, and may be disposed to face the adjacent cells 10.

[0043] Each of the first and second substrates may be formed of at least one material selected from the group consisting of resin, metal, and inorganic material other than metal, or may be a composite of these materials, and the type of the substrate is not limited. The form of the substrate is not particularly limited, and may be a film, thin film, sheet, or the like.

[0044] The resin may be, for example, one or more selected from the group consisting of polyethylene, polypropylene, polystyrene, polyethylene terephthalate, and polyamide.

[0045] The metal may be, for example, one or more selected from the group consisting of copper, nickel, cobalt, iron, chromium, vanadium, palladium, ruthenium, rhodium, molybdenum, tungsten, iridium, silver, gold, and platinum. When using a substrate made of the above metal material, the substrate may be subjected to anti-corrosion treatment, insulation treatment, etc., as necessary.

[0046] The inorganic material may be one or more selected from the group consisting of calcium carbonate (CaCO3), talc, and mica.

[0047] As a specific example, each of the first substrate and the second substrate may include an inorganic material, and more specifically, may include mica, thereby improving the heat insulation property and durability of the heat insulating sheet.

[0048] The aerogel layer may include an aerogel, a fibrous support, and a functional material including a binder, a dispersant, or a combination thereof.

[0049] The aerogel has a BET specific surface area of ​​500 m 2 / g~1,000m 2 For example, the aerogel may have a BET specific surface area of ​​500 m 2 / g~950m 2 / g, 550m 2 / g~950m 2 / g, or 600m 2 / g~900m 2 By including an aerogel having a BET specific surface area value within the above range, scattering of the aerogel particles can be prevented and heat insulation can be improved.

[0050] The particle size of the aerogel may be 5 μm to 200 μm, 10 μm to 100 μm, or 20 μm to 60 μm. By including an aerogel having a particle size within the above range, the heat insulating properties can be improved and the heat transfer between the multiple cells can be delayed.

[0051] The content of the aerogel may be 10% by weight to 90% by weight, 30% by weight to 70% by weight, or 40% by weight to 60% by weight based on the total amount of the aerogel layer. By including the aerogel within the above range, excellent heat insulating properties of the heat insulating sheet can be obtained.

[0052] On the other hand, aerogel is a transparent or translucent advanced material with a nanoporous structure, and has very low density and low thermal conductivity. As a result, it not only has great potential as an insulating material, but is also evaluated as a highly efficient super-insulating material that can be used in a variety of industrial fields.

[0053] The greatest advantage of aerogel is that it exhibits a lower thermal conductivity than conventional organic insulation materials such as styrofoam, and that it can solve the problem of fire vulnerability and generation of harmful gases during fire, which are fatal weaknesses of organic insulation materials. However, aerogel has a very low strength, such as being easily broken even by small impacts due to its high brittleness, and is difficult to process into a very thin thickness and shape, so that it is very difficult to manufacture an insulation material using aerogel alone, despite its excellent insulation properties. Therefore, in one embodiment, the durability of the aerogel layer can be improved by including a fibrous support and a functional material including a binder, a dispersant, or a combination thereof, and the generation of dust during external impacts and work can be prevented.

[0054] By including the fibrous support in the aerogel layer, the durability of the heat insulating sheet formed using the same can be improved.

[0055] The fibrous support may include fibers used as supports for ordinary heat insulating materials. For example, the fibrous support may be one or more selected from the group consisting of natural fibers, silica fibers, glass fibers, ceramic fibers, carbon fibers, graphite fibers, mineral fibers, and polymer fibers. As a specific example, the fibrous support may include glass fibers, but is not limited thereto.

[0056] The natural fibers may be, for example, one or more selected from the group consisting of hemp, jute, flax, coir, hemp, and cellulose.

[0057] The mineral fibers may be, for example, one or more mineral fibers selected from the group consisting of basalt, wollastonite, alumina, silica, slag, and rock.

[0058] The polymer fiber may be, for example, one or more selected from the group consisting of nylon, polyimide, polyamide, polybenzimidazole, polybenzoxazole, polyamideimide, polyethyleneterephthalate, polybutyleneterephthalate, polyester, polyethylene (PE), and polypropylene (PP). As a specific example, the polymer fiber may be, but is not limited to, one or more selected from the group consisting of polyimide, polyamide, and polybenzimidazole.

[0059] The fibrous support may be, for example, in the form of wool or chopped strands, but is not limited thereto.

[0060] The diameter of the fibrous support may be, for example, 0.1 μm to 20 μm, 0.1 μm to 15 μm, 0.1 μm to 5 μm, 1 μm to 15 μm, or 3 μm to 10 μm. By including a fibrous support having a diameter within the above range, the structure of the aerogel layer can be made stronger, and the production cost can be reduced.

[0061] The content of the fibrous support may be 5% by weight to 70% by weight, 25% by weight to 60% by weight, or 30% by weight to 50% by weight, based on the total amount of the aerogel layer. When an aerogel layer containing a fibrous support within the above range is formed to produce a heat insulating sheet, durability can be improved.

[0062] The binder may include a water-based polymer binder. For example, the water-based polymer binder may be at least one selected from the group consisting of a water-based polymer, an anionic water-soluble polymer, a cationic water-soluble polymer, and a water-dispersible polymer.

[0063] The aqueous polymer may be, for example, at least one selected from the group consisting of polyvinyl alcohol, polyethylene oxide, polyacrylamide, and polyvinylpyrrolidone, but is not limited thereto.

[0064] The anionic water-soluble polymer may be at least one selected from the group consisting of polymers having functional groups of carboxylic acid, sulfonic acid, sulfate, phosphate, and salts thereof. For example, the anionic water-soluble polymer may be a polymer having a carboxylic acid group, and a specific example thereof may include, but is not limited to, polymaleic acid.

[0065] The cationic water-soluble polymer may be at least one selected from the group consisting of polymers having functional groups of amine, ammonium, phosphonium, sulfonium, and salts thereof. For example, the cationic water-soluble polymer may be a polymer having an amine group, and a specific example may be at least one selected from the group consisting of polyethylene amine and polyamine, but is not limited thereto.

[0066] The water-dispersible polymer may be at least one selected from the group consisting of water-dispersible polyurethane and water-dispersible polyester, but is not limited thereto.

[0067] The binder may include a water-based polymer and a water-dispersible polymer, for example, a water-based polymer having binder properties as well as dispersion properties, and a water-dispersible polyurethane having fire-resistant properties, and a specific example thereof may include polyvinyl alcohol and water-dispersible polyurethane.

[0068] The weight ratio of the aqueous polymer and the water-dispersible polymer may be 1:1 to 1:5, 1:1 to 1:4, or 1:2 to 1:3. When the weight ratio of the aqueous polymer and the water-dispersible polymer is used in combination within the above range, the heat insulation property, dust resistance, and compressibility of the heat insulation sheet can be further improved as well as the fire resistance and mechanical properties.

[0069] The content of the binder may be 0.5% by weight to 20% by weight, 2% by weight to 15% by weight, or 8% by weight to 15% by weight, based on the total amount of the aerogel layer. A heat insulating sheet including an aerogel layer containing a binder within the above range may have improved dust characteristics.

[0070] The dispersant may be at least one selected from the group consisting of a surfactant, a silane coupling agent, and a phosphate salt. Specific examples of the dispersant include, but are not limited to, at least one of a nonionic surfactant, an anionic surfactant, an amphoteric surfactant, a natural surfactant such as lecithin, and a phosphate salt.

[0071] When the dispersant is further included, the dispersion of the aerogel is improved during the preparation of the aerogel layer, and the aerogel can be uniformly dispersed in the fibrous support.

[0072] The content of the dispersant may be 0.1% by weight to 6% by weight, 0.1% by weight to 5% by weight, or 0.1% by weight to 3% by weight, based on the total amount of the aerogel layer. By including the dispersant within the above range, the aerogel layer can be produced at low cost, and the aerogel layer can be used to produce a battery insulation sheet having excellent heat insulation properties, uniformity, and dust resistance.

[0073] In one embodiment, the binder and the dispersant may be included in a weight ratio of 1:0.001 to 1:0.67, 1:0.001 to 1:0.5, or 1:0.001 to 1:0.3. When the binder and the dispersant are used in combination in a weight ratio within this range, the aerogel may be more uniformly dispersed in the aerogel layer.

[0074] In one embodiment, the fibrous support may comprise 25% by weight to 60% by weight, the aerogel may comprise 30% by weight to 70% by weight, and the binder may comprise 2% by weight to 15% by weight, based on the total amount of the aerogel layer.

[0075] As a specific example, the aerogel layer may contain 30% to 50% by weight of the fibrous support, 40% to 60% by weight of the aerogel, and 8% to 15% by weight of the binder, relative to the total amount of the aerogel layer. When the aerogel layer is formed within the above ranges, excellent heat insulation can be achieved and durability can be improved, the bonding strength between the fibrous support and the aerogel can be improved, and dust generation can be prevented.

[0076] In one embodiment, the aerogel layer may contain, relative to the total amount of the aerogel layer, 25% by weight to 60% by weight of the fibrous support, 30% by weight to 70% by weight of the aerogel, 2% by weight to 15% by weight of the binder, and 0.1% by weight to 3% by weight of the dispersant.

[0077] As a specific example, the aerogel layer may contain 30% to 50% by weight of the fibrous support, 40% to 60% by weight of the aerogel, 5% to 10% by weight of the binder, and 0.1% to 2% by weight of the dispersant, relative to the total amount of the aerogel layer. When the aerogel layer is formed within the above ranges, excellent heat insulation can be achieved and durability can be improved, the bonding strength between the fibrous support and the aerogel can be improved, and dust generation can be prevented.

[0078] In one embodiment, the foam layer may be formed on two or more surfaces, including the upper surface, of edge sides between the upper surface and the lower surface of the insulation sheet, and may include a foam material that foams when the ambient temperature rises to 100° C. or higher. For example, the foam material foams when the ambient temperature rises to 100° C. to 200° C., 120° C. to 180° C., or 120° C. to 170° C., and the thickness of the foam layer increases due to the increase in volume, thereby filling empty spaces in the battery module and preventing the spread of flames.

[0079] The foam layer may be formed on both upper and lower opposing sides of the heat insulating sheet or on the entire side, where the upper and lower sides may refer to the upper and lower sides based on the shape in which the heat insulating sheet is arranged.

[0080] The heat insulating sheet includes an upper surface, a lower surface, and an edge surface between the upper surface and the lower surface, and when the upper surface and the lower surface of the heat insulating sheet face the adjacent cells, the edge surface of the heat insulating sheet may include an upper surface, a lower surface, a front surface, and a rear surface. Here, the foam layer may be formed on both surfaces of the heat insulating sheet that face each other vertically, i.e., on the upper and lower surfaces or on the entire side surfaces. As a specific example, the foam layer may be necessarily formed on the upper surface of the edge surface of the heat insulating sheet.

[0081] In the battery module, the foam layer may be formed by coating a part or an entirety of a portion of the insulation sheet that is exposed to the outside and that does not face the cells.

[0082] In the battery module, the foam layer may be formed by further coating a part or all of the cells adjacent to the insulation sheet.

[0083] For example, the foam layer may be formed on the entire side of the insulation sheet, in which case, when one cell is heated, the foaming component foams and expands to fill empty spaces in the battery module other than the spaces where the cells, the insulation sheet, and the foam layer are formed, thereby preventing the spread of flames.

[0084] As another example, the foam layer may be formed on both upper and lower opposing sides of the heat insulating sheet, in which case the installation of the foam layer can be minimized while effectively preventing flame propagation.

[0085] The foam layer may be formed to a thickness of 3% to 20%, 5% to 15%, or 5% to 10% of the thickness of the heat insulating sheet. By forming the foam layer to a thickness within the above range, it is possible to prevent the spread of flames when one cell is exposed to heat.

[0086] The foam layer may have a thickness after foaming of 1000% to 3000%, 1300% to 2500%, or 1700% to 2300% of the thickness before foaming. Specifically, the foam layer foams when the surrounding temperature rises to a certain level or higher, and the thickness after foaming may increase to 10 to 30 times, 13 to 25 times, or 17 to 23 times the thickness before foaming.

[0087] The battery module includes an empty space other than the space where the cells, the insulating sheet, and the foam layer are formed, and the thickness of the foam layer after foaming may be 200% or more, 200% to 500%, or 200% to 400% of the height of the empty space formed in the upper part of the battery module. Specifically, the thickness of the foam layer after foaming may be 2 times or more, 2 times to 5 times, or 2 times to 4 times the height of the empty space formed in the upper part of the battery module.

[0088] The foam layer may be formed such that the thickness of the foam layer formed on the upper side of the heat insulating sheet is 100% or more, 100% to 400%, 150% to 350%, or 200% to 350% of the thickness of the foam layer formed on the lower side. Specifically, the foam layer may be formed such that the thickness of the foam layer formed on the upper side of the heat insulating sheet is 1 time or more, 1 time to 4 times, 1.5 times to 3.5 times, or 2 times to 3.5 times the thickness of the foam layer formed on the lower side. By controlling the thickness ratio of the foam layers formed on the upper and lower sides of the side of the heat insulating sheet in this way, it is possible to effectively prevent flames from spreading during thermal exposure in one cell.

[0089] The foam layer may be formed of a foam material that foams and expands in volume when the ambient temperature rises to 100°C to 200°C, 120°C to 180°C, or 120°C to 170°C, and the foam material may include, for example, one or more foaming agents selected from the group consisting of expanded graphite, organic foaming agents, and inorganic foaming agents.

[0090] The organic foaming agent may be one or more selected from the group consisting of azodicarbonamide (ADCA), dinitro pentamethylene tetramine (DPT), and 4,4'-oxy bis(benzene sulfonyl hydrazide) (OBSH). The inorganic foaming agent may be one or more selected from the group consisting of hydrogen carbonates, carbonates, and organic acid salts.

[0091] The foaming material may be mixed with a polymeric material to form a coating liquid. The polymeric material is not particularly limited as long as it can control the thickness of the foamed layer after foaming and the foaming trigger temperature of the foaming material, and may be, for example, at least one selected from the group consisting of polyimide, polyamide, polybenzimidazole, polybenzoxazole, polyamideimide, polyurethane, polyethyleneterephtalate, polybutyleneterephtalate, polyester, polyethylene (PE), and polypropylene (PP).

[0092] Here, the coating liquid containing the foaming material and the polymeric material may foam and expand in volume when the ambient temperature rises to, for example, 100°C to 200°C, 120°C to 180°C, or 120°C to 170°C.

[0093] The foaming material and the polymeric material may form a coating liquid in a weight ratio of 1:9 to 5:5, 1:9 to 4:6, or 1:9 to 3:7.

[0094] A manufacturing method for a battery module according to one embodiment may include the steps of arranging a plurality of cells, arranging an insulation sheet between the plurality of cells such that an upper surface and a lower surface of the insulation sheet face adjacent cells, respectively, and forming a foam layer on two or more surfaces, including an upper surface, of edge sides between the upper surface and the lower surface of the insulation sheet.

[0095] In an embodiment, the arrangement of the plurality of cells in the step of arranging the plurality of cells is not particularly limited, and the plurality of cells may be appropriately arranged depending on the type of the battery.

[0096] In one embodiment, a heat insulating sheet may be disposed between each of the plurality of cells. The heat insulating sheet may be disposed such that an upper surface and a lower surface face the adjacent cells.

[0097] The method for producing the insulating sheet may include forming a first substrate, applying an aerogel composition onto the first substrate, and forming a second substrate on the applied aerogel composition.

[0098] The first and second substrates may be as described above, and the size and shape of the substrate may be appropriately adjusted according to the cell structure.

[0099] The aerogel composition may include a step of mixing a functional material, including a binder, a dispersant, or a combination thereof, with a solvent to prepare a solvent mixture, a step of mixing the solvent mixture and an aerogel to prepare an aerogel mixture, and a step of mixing the aerogel mixture and a fibrous support to prepare an aerogel composition.

[0100] In the step of preparing the solvent mixture by mixing the functional material with the solvent, a binder may be mixed with the solvent, or a binder and a dispersant may be mixed with the solvent.

[0101] The solvent may be one or more selected from the group consisting of polar solvents and non-polar solvents.

[0102] The polar solvent may be one or more selected from the group consisting of water and alcohol-based solvents.

[0103] The water may be, for example, one or more types selected from the group consisting of purified water and deionized water.

[0104] The alcohol-based solvent may be, for example, one or more selected from the group consisting of methanol, ethanol, propanol, pentanol, butanol, hexanol, ethylene glycol, propylene glycol, diethylene glycol, and glycerol, but is not limited thereto.

[0105] The non-polar solvent may include a hydrocarbon solvent, for example, one or more selected from the group consisting of hexane, pentane, heptane, toluene, and benzene, and more preferably, an alkane solvent such as hexane, or a mixture containing an alkane solvent, but is not limited thereto.

[0106] The solvent may include water. When water is used as the solvent, raw material costs and post-treatment costs can be effectively reduced. However, when water is used as the solvent, there is a problem that it is not easy to mix with the hydrophobic aerogel. In one embodiment, the aerogel is uniformly dispersed by controlling the mixing stage design, mixing conditions, addition and amount of binder and dispersant, etc. When the aerogel is uniformly dispersed in the composition in this way, a heat insulating sheet having excellent heat insulating properties, durability, and low dust properties can be formed with a thin thickness without using a large amount of binder.

[0107] The solvent may be contained in such a way that the weight ratio of the solvent to the total amount of solids in the aerogel composition is 1:1 to 1:90. For example, the weight ratio of the solvent to the total amount of solids in the aerogel composition may be 1:50 to 1:70, 1:20 to 1:30, or 1:2 to 1:10. By controlling the weight ratio of the solvent to the total amount of solids within the above range, it is possible to achieve both dispersibility, coatability, and phase stability.

[0108] The specific explanation regarding the binder and dispersant may be as described above.

[0109] In the step of preparing the aerogel mixture by mixing the solvent mixture and the aerogel, the specific description of the aerogel may be the same as that described above.

[0110] In the step of preparing an aerogel composition by mixing the aerogel mixture and the fibrous support, the specific description of the fibrous support may be as described above.

[0111] In each of the steps of preparing a solvent mixture by mixing a functional material including a binder, a dispersant, or a combination thereof with the solvent, preparing an aerogel mixture by mixing the solvent mixture and an aerogel, and preparing an aerogel composition by mixing the aerogel mixture and a fibrous support, a mixer may be used during mixing. For example, the mixer may include, but is not limited to, a planetary mixer, a PD mixer, a thinky mixer, a C-mixer, etc.

[0112] As a specific example, a planetary mixer may be used to mix the solvent mixture and the aerogel. When the solvent mixture and the aerogel are mixed using the planetary mixer, the aerogel can be uniformly dispersed in the solvent.

[0113] The planetary mixer may be a device that can be used to mix or stir different materials to produce a homogenous mixture, and may include blades that are capable of planetary motion.

[0114] In one embodiment, the planetary mixer may include one or more planetary blades and one or more high-speed dispersion blades. As a specific example, the planetary mixer may include one or more planetary blades and one or more high-speed dispersion blades.

[0115] The planetary blades and high speed dispersion blades rotate continuously about their axes, and the rotational speed may be expressed in units of rotations per minute (rpm).

[0116] In one embodiment, the planetary mixer may include a first blade and a second blade having different rotation axes. For example, the first blade may be a low-speed blade, and the second blade may be a high-speed blade. Here, low speed and high speed refer to the relative rotation speeds of the first blade and the second blade. As a specific example, the first blade may be an open blade, and the second blade may be a Despa blade.

[0117] The rotation speed of the first blade may be, for example, 10 rpm to 100 rpm, 10 rpm to 60, or 30 rpm to 70 rpm. The rotation speed of the second blade may be, for example, 100 rpm to 2000 rpm, 100 rpm to 1000 rpm, 300 rpm to 1700 rpm, or 500 rpm to 1700 rpm.

[0118] When the functional material is mixed in the solvent, the rotation speed of the first blade may be 10 rpm to 60 rpm, 20 rpm to 50 rpm, or 30 rpm to 40 rpm, and the rotation speed of the second blade may be 300 rpm to 1700 rpm, 600 rpm to 1000 rpm, or 700 rpm to 800 rpm. By mixing the solvent and the functional material as described above, a solvent mixture in which the binder, dispersant, or a combination thereof is uniformly dispersed is prepared, and aerogel mixing in the subsequent step can be performed more easily.

[0119] When the solvent mixture and the aerogel powder are mixed, the rotation speed of the first blade of the mixer may be 30 rpm to 70 rpm, 40 rpm to 70 rpm, or 60 rpm to 70 rpm, and the rotation speed of the second blade may be 500 rpm to 1700 rpm, 600 rpm to 1600 rpm, or 800 rpm to 1500 rpm. By adding the aerogel powder to the solvent mixture and mixing it as described above, it is possible to prevent the aerogel powder from agglomerating with each other and induce uniform dispersion.

[0120] When the aerogel mixture and the fibrous support are mixed, the rotation speed of the first blade of the mixer may be 10 rpm to 60 rpm, 20 rpm to 50 rpm, or 30 rpm to 40 rpm, and the rotation speed of the second blade may be 300 rpm to 1700 rpm, 400 rpm to 1500 rpm, or 800 rpm to 1200 rpm. When the aerogel mixture and the fibrous support are mixed in this way, the air bubbles in the composition are removed, the viscosity is adjusted, and the fibrous support is easily dispersed between the uniformly dispersed aerogel, so that the aerogel may be present in the composition in a form in which the periphery of the fibrous support is covered by the aerogel. Here, a binder is present between the aerogel and the fibrous support, which can improve the binding force between the aerogel and the fibrous support.

[0121] By forming an insulating sheet using a method according to an embodiment, durability as well as insulating properties are improved, and dust generation due to the aerogel falling off during manufacturing the insulating sheet, installation inside an apparatus, or when external vibration occurs can be prevented.

[0122] In one embodiment, the step of forming a foam layer on two or more of the edge sides between the upper and lower surfaces of the insulation sheet, including the upper surface, may be performed before or after placing the insulation sheet between the multiple cells.

[0123] For example, the step of forming the foam layer may be performed before the insulation sheet is disposed between the cells. In this case, after the insulation sheet is manufactured, foam layers may be formed on two or more sides of the insulation sheet, including an upper side, and the insulation sheets with the foam layers formed thereon may be disposed between the cells.

[0124] The foam layer may be formed by a method such as coating, dipping, casting, etc. Specifically, a solution containing a foaming agent may be applied to two or more sides of the heat insulating sheet, including the upper side, and the foam layer may be formed by coating, dipping, or casting.

[0125] As another example, the step of forming the foam layer may be performed after disposing the heat insulating sheet between the cells. In this case, the heat insulating sheet may be disposed between the cells, and the foam layer may be formed on two or more sides of the heat insulating sheet, including the upper side.

[0126] The foam layer may be formed by an injection method. Specifically, a foam layer may be formed by injecting a solution containing a foaming agent or the foaming agent itself into two or more sides of the insulating sheet, including an upper side, using a dispenser, injector, etc., inside the battery module in which the plurality of cells and the insulating sheet are disposed.

[0127] An embodiment includes a battery pack including the battery module. A plurality of battery modules may be disposed within the battery pack.

[0128] Specific examples of the present invention will be presented below. However, the examples described below are merely for the purpose of specifically illustrating or explaining the present invention, and the present invention should not be limited thereto. Furthermore, since the contents not described here can be sufficiently inferred by a person skilled in the art, the description thereof will be omitted.

[0129] (Battery module manufacturing) Example 1 1.Insulation sheet manufacturing Polyvinyl alcohol (Sigma Aldrich, Poly(vinyl alcohol)) was added as a binder to ultrapure water as a solvent, and then mixed under conditions of an open blade of 30 rpm and a despa blade of 700 rpm to produce a solvent mixture. 2 Aerogel mixture was prepared by adding aerogel having a particle size of 1 / g and mixing with an open blade at 70 rpm and a Despa blade at 1500 rpm. Glass wool was added to the aerogel mixture and mixing with an open blade at 30 rpm and a Despa blade at 1200 rpm to prepare an aerogel composition. A planetary mixer (DIENTEK, PT-005) was used for mixing.

[0130] The solid content of the prepared aerogel composition was confirmed to be 50 wt % aerogel, 40 wt % glass wool, and 10 wt % polyvinyl alcohol.

[0131] The prepared aerogel composition was applied as a slurry onto a 0.3 mm thick mica sheet (Famica, Muscovite), and then another 0.3 mm thick mica sheet was laminated in a sandwich type and coated by a roll rolling method.

[0132] It was confirmed that the total thickness of the produced heat insulating sheet was 3 mm, the thickness of the aerogel layer was 2.4 mm, and the thickness of each of the mica sheets was 0.3 mm.

[0133] 2. Foam layer manufacturing A water-based thermally decomposable expandable coating liquid (Lord, Sipiol FR220) was applied to the entire side of the heat insulating sheet using a brush to form a foam layer, and the thickness of the foam layer was confirmed to be 0.15 mm.

[0134] 3. Battery module manufacturing A plurality of cells were arranged in a battery module, and a heat insulating sheet having a foam layer formed thereon was arranged between each of the plurality of cells.

[0135] Example 2 The manufacturing method was the same as that of Example 1, except that the thickness of the foamed layer was changed to 0.25 mm.

[0136] Example 3 The manufacturing method was the same as that of Example 1, except that the thickness of the foamed layer was changed to 0.1 mm.

[0137] Example 4 The manufacturing method was the same as that of Example 1, except that the thickness of the foamed layer was changed to 0.35 mm.

[0138] Example 5 The foam layer was formed in the same manner as in Example 1, except that the foam layer formed on the upper part of the side of the insulation sheet was 0.2 mm thick, and the foam layer formed on the remaining side of the insulation sheet was 0.1 mm thick.

[0139] Example 6 The heat insulating sheet was produced in the same manner as in Example 1, except that the foam layers were formed only on both upper and lower opposing sides of the heat insulating sheet, that is, only on the upper and lower sides of the heat insulating sheet.

[0140] Comparative Example 1 The aerogel layer was formed using only aerogel in Example 1, and heat insulating sheets without foam layers were placed between the cells, respectively, in the same manner as in Example 1. In this case, it was difficult to form a heat insulating sheet due to the absence of a binder, and the heat propagation prevention effect could not be obtained.

[0141] Comparative Example 2 The heat insulating sheet was manufactured in the same manner as in Example 1, except that the foam layer was formed on the upper and lower surfaces of the heat insulating sheet, rather than on the side surfaces of the heat insulating sheet in Example 1. Here, the total thickness of the manufactured heat insulating sheet was the same as in Example 1, and it was confirmed that the foam layer was formed on the upper and lower surfaces of the heat insulating sheet with a thickness of 0.15 mm, and therefore the aerogel layer was formed with a thickness of 2.1 mm.

[0142] (Experimental Example) Experimental Example 1: Evaluation of thickness increase rate before and after foaming of foam layer The thickness increase rate of the foam layers prepared in Examples 1 to 4 and Comparative Example 2 was evaluated.

[0143] Specifically, the thickness of each of the insulation sheets having the foam layers formed thereon was measured before foaming, and the insulation sheets were fixed at the top and bottom and then heated for 3 minutes using a micro torch to foam the foam layers, and the thickness after foaming was measured and the thickness expanded upward after foaming was calculated. The results are shown in Table 1 below.

[0144] Experimental example 2: Evaluation of the physical properties of heat insulating sheets 1.Insulation evaluation The heat insulation properties were evaluated using the heat insulation sheets manufactured in Examples 1 to 4 and Comparative Example 2. Here, in Examples 1 to 4 and Comparative Example 2, the heat insulation sheet may refer to a heat insulation sheet having a foamed layer formed thereon.

[0145] Specifically, each insulation sheet was placed between a pair of opposing 1T thick aluminum plates, which were then placed on a heat press, and the upper plate of the heat press was heated to 350°C, while the lower plate of the heat press was not heated and was kept at the starting temperature of 40°C. A pressure of 20 kN was then applied to the lower plate of the heat press, and the maximum temperature of the lower plate of the heat press after 11 minutes was measured, and the results are shown in Table 1 below.

[0146] 2.Compressibility evaluation Compression performance was evaluated using the heat insulating sheets manufactured in Examples 1 to 4 and Comparative Example 2. Here, in Examples 1 to 4 and Comparative Example 2, the heat insulating sheet may refer to a heat insulating sheet having a foamed layer formed thereon.

[0147] Specifically, the thickness ratio when a load of 5kN was applied to the UTM equipment was measured based on the thickness when a load of 40kN was applied, and is shown in Table 1 below.

[0148] Experimental example 3: Heat transfer evaluation The battery modules manufactured in Examples 1 to 4 and Comparative Example 2 were evaluated for flame propagation.

[0149] Specifically, the heat transfer was evaluated by a method of transferring heat under nail penetration conditions using a 50 Ah rectangular (NCM 811 / Graphite) 2-cell simplified module device with an upper cover attached and a gap between the top of the cell and the cover of 1.5 mm. The results are shown in Table 1 below.

[0150] [Table 1]

[0151] Referring to Table 1 above, in comparison with Examples 1 to 4, in Comparative Example 2, the foam layer was formed on the front and rear sides of the heat insulating sheet, so the thickness of the foam layer extending upward was small, and the ratio of the aerogel layer was low under the same thickness condition, and both the heat insulating property and compressibility were reduced. In particular, in Examples 1 and 2, when the foam layer was formed on the entire side of the heat insulating sheet and the thickness of the foam layer was controlled to 5% to 10% of the total thickness of the heat insulating sheet, it was confirmed that the thickness increase efficiency relative to the thickness of the foam layer was excellent, and the heat insulating property, compressibility, fire resistance and flame retardancy were more excellent.

[0152] On the other hand, it was also confirmed that a sufficient heat propagation prevention effect can be obtained when the foam layer on the lower side of the side of the insulation sheet is made slightly thinner than that on the upper side, as in Example 5, or when the foam layer is formed only on the upper and lower sides of the side of the insulation sheet, as in Example 6.

[0153] Therefore, it has been confirmed that the battery module according to one embodiment has excellent insulation properties, compressibility, and flame resistance due to the structure in which an insulating sheet is disposed between multiple cells and a foam layer is formed on the side of the insulating sheet.

[0154] Although the preferred embodiments of the present invention have been described above, the present invention is not limited thereto, and various modifications can be made within the scope of the claims, the detailed description of the invention, and the accompanying drawings, and it is to be understood that these modifications also fall within the scope of the present invention. [Explanation of symbols]

[0155] 10 Cells 20. Heat Insulation Sheet 21 First base material 22 Second base material 23 Aerogel layer 30 Foam layer 100 Battery Module

Claims

1. A plurality of cells; A heat insulating sheet provided between each of the plurality of cells, the upper surface and the lower surface of each of which are arranged to face an adjacent cell; a foam layer formed on two or more surfaces, including an upper surface, of edge sides between an upper surface and a lower surface of the insulation sheet.

2. The battery module according to claim 1 , wherein the cells are secondary battery cells.

3. The heat insulating sheet is A first substrate; A second substrate; The battery module according to claim 1 , further comprising an aerogel layer disposed between the first substrate and the second substrate.

4. The battery module according to claim 3 , wherein each of the first substrate and the second substrate is formed of at least one material selected from the group consisting of a resin, a metal, and an inorganic material other than a metal.

5. 4. The battery module according to claim 3, wherein the aerogel layer comprises an aerogel, a fibrous support, and a functional material comprising a binder, a dispersant, or a combination thereof.

6. The aerogel has a BET specific surface area of ​​500 m ２ / g to 1,000m ２ The battery module according to claim 5 , wherein the tensile strength is 1 / g.

7. 6. The battery module according to claim 5, wherein the fibrous support is at least one selected from the group consisting of natural fibers, silica fibers, glass fibers, ceramic fibers, carbon fibers, graphite fibers, mineral fibers, and polymer fibers.

8. The battery module according to claim 5 , wherein the binder comprises a water-based polymer binder.

9. The battery module according to claim 5 , wherein the dispersant is at least one selected from the group consisting of a surfactant, a silane coupling agent, and a phosphate-based salt.

10. The battery module according to claim 5, wherein the aerogel layer comprises, with respect to a total amount of the aerogel, 10% by weight to 90% by weight of the aerogel, 5% by weight to 70% by weight of the fibrous support, and 0.5% by weight to 20% by weight of the functional material.

11. The battery module of claim 1 , wherein the foam layer comprises a foam material that foams when the ambient temperature rises to 100° C. to 200° C.

12. The battery module according to claim 1 , wherein the foam layer is made of at least one material selected from the group consisting of expanded graphite, an organic foaming agent, and an inorganic foaming agent.

13. The organic foaming agent is at least one selected from the group consisting of azodicarbonamide, dinitropentamethylenetetramine, and oxybis(benzenesulfonylhydrazide); The battery module according to claim 12 , wherein the inorganic foaming agent is at least one selected from the group consisting of hydrogen carbonates, carbonates, and organic acid salts.

14. The battery module according to claim 1 , wherein the foam layer has a thickness that is 3% to 20% of the thickness of the insulating sheet.

15. The battery module of claim 1 , wherein the foam layer has a thickness after foaming that is 1000% to 3000% of the thickness before foaming.

16. The battery module according to claim 1 , wherein the foam layer is formed on both upper and lower opposing sides of the insulating sheet or on the entire side surface.

17. The battery module of claim 16 , wherein a thickness of the foam layer formed on an upper surface of the insulation sheet is 100% or more of a thickness of the foam layer formed on a lower surface of the insulation sheet.

18. disposing a plurality of cells; disposing an insulating sheet between the cells such that the upper and lower surfaces of the insulating sheet face adjacent cells; forming a foam layer on at least two of the edge surfaces between the upper and lower surfaces of the insulation sheet, including the upper surface.

19. The method of claim 18 , wherein the forming of the foam layer is performed before or after the insulating sheet is disposed between the plurality of cells.

20. A battery pack comprising the battery module according to any one of claims 1 to 17.

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